The GC/MS-NCI technique has been established previously in our laboratory for the measurement of trace levels of neurosteroids in human plasma and cerebro spinal fluid (CSF)and the analysis of rat tissue samples. We were able to establish a procedure to quantify pregnenolone, 5a,3a-, 5b,3a-, 5a,3b-THP, and dihydrotestosterone, dihydroprogesterone and progesterone in these samples. During this period, no staff time was devoted to obtain new data although the project has not been inactivated completely.